Madison Olson knows plenty about elves, particularly the one that lives in an ash tree on the south side of Lake Harriet.

“He’s married to a fairy,” the 3-year-old said rather emphatically. “And he can see us, but we can’t see him.”

While Mr. Little Guy’s marriage to a fairy can neither be confirmed nor denied, Olson’s got one thing right — the Lake Harriet Elf is always watching.

And for almost 20 years, he’s also been answering the hundreds of letters delivered to his tiny doorstep between Memorial Day and Labor Day each year.

The Elf, also known as Mr. Little Guy and sometimes Thom, has become a much-loved Minneapolis figure; his letters, a cherished possession for children throughout the Twin Cities and beyond.

Go online: While the Lake Harriet Elf corresponds almost exclusive by paper, he does have a website. You can visit it at http://mrlittleguy.com/

Some residents have even asked the Minneapolis City Council to recognize the Elf’s good deeds, possibly on his birthday, which is Aug. 15. Those plans are currently being developed, but Council Member Linea Palmisano confirmed there will likely be a proclamation, “for his efforts to foster community around Lake Harriet.”

“I think that would be such a fantastic idea,” said Julie Olson, Madison’s mother. “He’s been answering letters for so long now that he deserves some recognition. That can’t be easy for a little guy. I mean, where does he get the tiny pens?”

At a tiny store? Who knows?

Here’s what is known about the Lake Harriet Elf, pieced together by his letters: He’s taller than his younger brother and shorter than his older brother. He likes to eat minnow cake and pizza, loves baking chocolate chip cookies and gets a lot of his jokes from ladybugs. He cooks on a grill made from a walnut shell, his bicycle is the size of a mushroom and his bedroom is wallpapered with notes written by “big people.”

Over the past two decades, he’s seen a rival elf open shop in another tree and another start a Facebook page. “I’m amazed it’s been almost 20 years,” Mr. Little Guy said, granting a rare interview request.

During his letter-writing heyday, he responded to about 2,000 letters a season. These days it’s between 1,000 and 1,500, he said. Those numbers — and unfortunately incidents of door vandalism — tend to increase any time something is written about him. (Sorry, Mr. Little Guy.)

Last week, the elf received letters from a child who wanted to know how tall he was. A vacation Bible school class in Woodbury delivered its greetings in a tightly wrapped scroll. Another simply wanted him to know there were ducks on the lake.

Each letter is unique, and many have left an indelible mark on the Elf’s heart. “It’s the cancer patient, or the child from a broken home,” he said. “Or, sometimes, I’ll get a little from an adult who wants to know when will they ever find a job. Sometimes it’s a heavy burden for such small shoulders.”

Still, the Elf has no immediate plans to stop writing letters. Or plans to vacate his tree for fancier digs.

“Honestly, I don’t know how to quit,” he laughed.

We’re relieved, Mr. Little Guy. So is Madison, who has yet to write her first letter to the Elf. She’s still working on printing her name.

Instead, Madison presses her tiny mouth against the tiny door in the tree and shouts, “Don’t worry, I’ll be back.”